Beyond Olfaction: New Insights into Human Odorant Binding Proteins
Journal:
arXiv
Published Date:
Jul 4, 2025
Abstract
Until today, the exact function of mammalian odorant binding proteins (OBPs)
remains a topic of debate. Although their main established function lacks
direct evidence in human olfaction, OBPs are traditionally believed to act as
odorant transporters in the olfactory sense, which led to the exploration of
OBPs as biomimetic sensor units in artificial noses. Now, available RNA-seq and
proteomics data identified the expression of human OBPs (hOBP2A and hOBP2B) in
both, male and female reproductive tissues. This observation prompted the
conjecture that OBPs may possess functions that go beyond the olfactory sense,
potentially as hormone transporters. Such a function could further link them to
the tumorigenesis and cancer progression of hormone dependent cancer types
including ovarian, breast, prostate and uterine cancer. In this structured
review, we use available data to explore the effects of genetic alterations
such as somatic copy number aberrations and single nucleotide variants on OBP
function and their corresponding gene expression profiles. Our computational
analyses suggest that somatic copy number aberrations in OBPs are associated
with large changes in gene expression in reproductive cancers while point
mutations have little to no effect. Additionally, the structural
characteristics of OBPs, together with other lipocalin family members, allow us
to explore putative functions within the context of cancer biology. Our
overview consolidates current knowledge on putative human OBP functions, their
expression patterns, and structural features. Finally, it provides an overview
on applications, highlighting emerging hypotheses and future research
directions within olfactory and non-olfactory roles.
